Limbo is an old version of Mambo that runs on text files but operates the same.. (Mambo is now Joomla..)..
I believe it's called flat file when not using a db Check Wikipedia entry - they have a few listed: http://en.wikipedia.org/wiki/List_of_content_management_systems#File_.2F_Flat_file
You mean guys, they use flat file to store the data? I just can't imagine how scalable that flat file will be in the future if there's a big amount of information strored..